• Journal of Technologic Dentistry
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• v.36 no.2
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• pp.91-96
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• 2014

Purpose: The purpose of this study was evaluate the validity of polyurethane model fabricated by intra oral scanning method. Methods: Ten sam cases of stone models were manufactured from master model, and polyurethane models were made with the intra oral scanning and CNC milling method. One examiner individually measured 6 distances(intercanine distance, intermolar distance, two dental arch lengths(right, left) and two diagonal of dental arch lengths(right, left) on the stone models and the polyurethane models. The Mann-Whitney U test(${\alpha}$=0.05) were used for statistical analysis. Results: The mean difference between measurements made directly on the stone models and those made on the polyurethane models was 0.31-0.38mm. No statistically differences between the two groups were founded 4 distances(p>0.05), but 2 distances were statistically significant(p<0.05). Conclusion: Stone models showed larger than polyurethane models fabricated by intra oral scanning method.

• The Journal of the Korean dental association
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• v.52 no.6
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• pp.354-362
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• 2014

With the development of digital dentistry, various intra-oral scanners which acquire intraoral image without conventional impression taking and stone pouring steps have been introduced. Fixed dental prostheses such as inlay, onlay, crown, and bridge fabricated by CAD/CAM technique combined with digital impressions is getting popular due to the recent rapid progress of digital impression taking system. In comparison with traditional prosthetic procedure, the advantages of intraoral image acquiring and CAD/CAM technique are as follows; the omission of conventional impression materials, reduced workflow step, and increased efficiency by online communication with clinic and laboratory. This review article covers some opinions about the suitable scanning procedures for the various prosthodontic treatments and the utilization of digital intraoral scanner and CAD/CAM system.

• Imaging Science in Dentistry
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• v.35 no.2
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• pp.97-103
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• 2005

Purpose : To determine if ultrasonography is a reliable technique to assess masseter muscle sites within intra- and interobserver and the scanning level and/or the muscle condition affect local cross-sectional dismension (LCSD) measurements of masseter muscle. Materials and Methods : 10 subjects without sign and symptom of temporomandibular disorders and missing posterior teeth were examined by ultrasonography. Bilateral ultrasonographic examinations were performed with a linear (B-scan) 7.5 MHz small-part transducer to register LCSDS of the masseter muscle on three different levels. Scans were made on relaxed and clenching condition. Three oral and maxillofacial radiologists measured at two sessions with a time interval of at least 5 minutes. Results : Variables such as 'condition' and 'level' had a significant effect on muscle measurements (p<0.05). There was no significant difference between 'sessions'(p>0.05) and 'observers' (p>0.05). LCSDS on lower scan level were significantly thinner than those on upper and middle level. Those on clenching condition were significantly thicker than those on relaxed condition (p<0.05). The scanning level with the highest reproducibility was middle with clenching condition (ICC=0.90, $MSE=0.55\%$). Conclusion : The data suggested that ultrasonography was a reliable method for measuring LSCD of masseter muscle in intra- and Interobserver and middle scan level showed the most reliable data.

• The Journal of Advanced Prosthodontics
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• v.9 no.5
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• pp.381-386
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• 2017

PURPOSE. To integrate extra-oral facial scanning information with CAD/CAM complete dentures to immediately rehabilitate terminal dentition. MATERIALS AND METHODS. Ten patients with terminal dentition scheduled for total extraction and immediate denture placement were recruited for this study. The patients were submitted to a facial scanning procedure using the in-office PritiMirror scanner with bite registration records in-situ. Definitive stone cast models and bite records were subsequently submitted to a lab scanning procedure using the lab scanner (iSeries DWOS; Dental Wings). The scanned models were used to create a virtual teeth setup of a complete denture. Using the intra-oral bite records as a reference, the virtual setup was incorporated in the facial scan thereby facilitating a virtual clinical evaluation (teeth try-in) phase. After applying necessary adjustments, the virtual setup was submitted to a CAM procedure where a 5-axis industrial milling machine (M7 CNC; Darton AG General) was used to fabricate a full-milled PMMA immediate provisional prosthesis. RESULTS. Total extractions were performed, the dentures were immediately inserted, and subjective clinical fit was evaluated. The immediate provisional prostheses were inserted and clinical fit, occlusion/articulation, and esthetics were subjectively assessed; the results were deemed satisfactory. All provisional prostheses remained three months in function with no notable technical complications. CONCLUSION. Ten patients with terminal dentition were treated using a complete digital approach to fabricate complete dentures using CAD/CAM technology. The proposed technique has the potential to accelerate the rehabilitation procedure starting from immediate denture to final implant-supported prosthesis leading to more predictable functional and aesthetics outcomes.

• The Journal of the Korean dental association
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• v.56 no.11
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• pp.616-621
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• 2018

This clinical case highlights the failure of long length implants, and the prosthodontic procedures necessary to rehabilitate the maxillary dentition of a patient with microstomia. The integrated digital technology of intra-oral scanning, computer-aided design, and three-dimensional printing can provide an alternative method to make conventional impressions for patients with microstomia who cannot insert the appropriate tray in their mouths.

• Imaging Science in Dentistry
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• v.43 no.2
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• pp.63-69
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• 2013

After over one decade development, cone beam computed tomography (CBCT) has been widely accepted for clinical application in almost every field of dentistry. Meanwhile, the radiation dose of CBCT to patient has also caused broad concern. According to the literature, the effective radiation doses of CBCTs in nowadays market fall into a considerably wide range that is from $19{\mu}Sv$ to $1073{\mu}Sv$ and closely related to the imaging detector, field of view, and voxel sizes used for scanning. To deeply understand the potential risk from CBCT, this report also reviewed the effective doses from literatures on intra-oral radiograph, panoramic radiograph, lateral and posteroanterior cephalometric radiograph, multi-slice CT, and so on. The protection effect of thyroid collar and leaded glasses were also reviewed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.197-202
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• 2018

This study was conducted to evaluate the distortion and data accuracy that may occur depending on the methods employed by the oral scanner (intra-oral scanner). Deseutap 3D models employing a plaster model used clinically as a scanner to create a standard scan data using the same model, separated by oral scanners in three different ways (AS Group, ZS group, OS group) How to scan each 5 times made the scan data for each group, it shows the 0.121 mm, 0.172 mm AS group, OS group 0.423 mm accuracy in ZS group. The ZS group showed the highest accuracy, with maximum error values of 0.113 mm, 0.169 mm and 0.246 being observed for the ZS, AS and OS group, respectively. The three scanning methods showed a clear differences in accuracy and reproducibility and also appeared to be meaningful in clinical practice.

• The korean journal of orthodontics
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• v.44 no.2
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• pp.69-76
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• 2014

Objective: This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Methods: Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of interexaminer and inter-method variability. Results: The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. Conclusions: The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.50 no.1
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• pp.13-26
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• 2024

Objectives: The aim of this study was to perform a comparative analysis of the ultrastructural and chemical composition of sialoliths, tonsilloliths, and antroliths and to describe their growth pattern. Materials and Methods: We obtained 19 specimens from 18 patients and classified the specimens into three groups: sialolith (A), tonsillolith (B), and antrolith (C). The peripheral, middle, and core regions of the specimens were examined in detail by histology, micro-computed tomography (micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy, and transmission electron microscopy (TEM). Results: In the micro-CT, group A showed alternating radiodense and radiolucent layers, while group B had a homogeneous structure. Group C specimens revealed a compact homogeneous structure. Histopathologically, group A showed a laminated, teardrop-shaped, globular structure. Group B demonstrated degrees of immature calcification of organic and inorganic materials. In group C, the lesion was not encapsulated and showed a homogeneous lamellar bone structure. SEM revealed that group A showed distinct three layers: a peripheral multilayer zone, intermediate compact zone, and the central nidus area; groups B and C did not show these layers. The main elemental components of sialoliths were O, C, Ca, N, Cu, P, Zn, Si, Zr, F, Na, and Mg. In group B, a small amount of Fe was found in the peripheral region. Group C had a shorter component list: Ca, C, O, P, F, N, Si, Na, and Mg. TEM analysis of group A showed globular structures undergoing intra-vesicular calcification. In group B, bacteria were present in the middle layer. In the outer layer of the group C antrolith, an osteoblastic rimming was observed. Conclusion: Sialoliths had distinct three layers: a peripheral multilayer zone, an intermediate compact zone and the central nidus area, while the tonsillolith and antrolith specimens lacked distinct layers and a core.

• The Journal of the Korean dental association
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• v.52 no.1
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• pp.17-26
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• 2014

Computerized 3D virtual dental models are currently available, and their use has started to improve treatment outcomes. The accuracy of digital models has been demonstrated by many studies and various intra-oral scanners are innovated for short scanning time and high precision. Recently, a digital model was combined with a high technology computer-driven system, which was developed for the application of a digital set-up and indirect bonding of lingual attachments. In this section, virtual treatment planning using a virtual set-up program is be introduced, and the clinical applications and accuracy of computer-generated indirect bonding are discussed.